Summary

In matplotlib <v3.6 TriMesh could be imported via

from matplotlib.tri import TriMesh

since v3.6 i get the following error:

ImportError: cannot import 'TriMesh' from 'matplotlib.tri' ...

The correct import now is

from matplotlib.collections import TriMesh

Proposed fix

maybe allow TriMesh import from matplotlib.tri for backward-compatibility reasons?